To meet the demand for wireless data traffic having increased since deployment of 4G communication systems, efforts have been made to develop an improved 5G or pre-5G communication system. Therefore, the 5G or pre-5G communication system is also called a ‘Beyond 4G Network’ or a ‘Post LTE System’.
The 5G communication system is considered to be implemented in higher frequency (mmWave) bands, e.g., 60 GHz bands, so as to accomplish higher data rates. To decrease propagation loss of the radio waves and increase the transmission distance, the beamforming, massive multiple-input multiple-output (MIMO), Full Dimensional MIMO (FD-MIMO), array antenna, an analog beam forming, large scale antenna techniques are discussed in 5G communication systems.
In addition, in 5G communication systems, development for system network improvement is under way based on advanced small cells, cloud Radio Access Networks (RANs), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul, moving network, cooperative communication, Coordinated Multi-Points (CoMP), reception-end interference cancellation, and the like.
In the 5G system, Hybrid FSK and QAM Modulation (FQAM) and sliding window superposition coding (SWSC) as an advanced coding modulation (ACM), and filter bank multi carrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA) as an advanced access technology have been developed.
With the rapid popularization of smartphones, various smartphone-based application services are used and this tendency is likely to continue. In line with this tendency, various techniques are discussed to overcome the data congestion caused by the various application services in the cellular system. For example, device-to-device (D2D) communication is a technique to distribute the load of the evolved node B (eNB) which is aggravated by large volume of mobile contents efficiently.
There are various methods for a terminal to locate a position. Representative position locating methods are categorized into the absolute position locating method based on the triangulation technique utilizing global positioning system (GPS) signals or information of multiple base stations and the relative position locating method based on the signal transmission and reception powers.
FIG. 1 is a diagram illustrating an absolute position locating method among terminal positioning methods in a wireless communication system according to the related art.
Referring to FIG. 1, the GPS-based technique as one of the absolute position locating methods determines the locations of the satellites and the GPS receiver based on the signals transmitted by three or more GPS satellites 120 and 125. By calculating the difference between the signal transmission times at the satellites and the signal reception time at the receiver, it is possible to acquire the distance between the satellite and the receiver and, in this case, the transmitted signal includes the information on the location of the GPS satellites 120 and 125.
Referring to FIG. 1, the triangulation technique using a plurality of base stations as another absolute position locating method locates the position of a terminal 100 through triangulation using the position coordinates of neighboring base stations 105, 110, and 115.
FIG. 2 is a diagram illustrating a relative position locating method among terminal positioning methods in a wireless communication system according to the related art.
Referring to FIG. 2, the relative position locating method operates in such a way that a transmit (Tx) terminal 200 provides a receive (Rx) terminal 205 with transmit power information and the Rx terminal 205 estimates a relative distance using the difference between the transmit power and the receive power.
The GPS receiver-based position locating method as one of the absolute position locating methods has a drawback in that the position locating accuracy drops in an indoor environment, a downtown area surrounded by buildings, or a thickly-wooded forest due to the low received signal strength of GPS. In the case of the base station-assisted position locating method which is another absolute position locating method, the position locating error may occur in the downtown area surrounded by huge skyscrapers.
In the case of the relative position locating method based on the transmit power information, there are many elements influencing the accuracy of the distance measurement significantly, such as signal reflection and refraction, multipath propagation, and signal attenuation, and the like.
In the current D2D communication, it is considered to use a signal-based relative position locating method for measuring a distance using the difference between the transmit (Tx) and receive (Rx) powers. The signal-based distance measurement method has low distance estimation accuracy and thus, may make the users subscribed to the services utilizing the distance information feel inconvenienced due to the low accuracy.
In addition, the signal information-based relative position locating method requires an extra operation for transmitting the signal information in addition to the basic discovery operation in the D2D communication. The basic discovery operation in the current D2D communication has been designed with consideration of signal information transmission for distance estimation.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.